The index of refraction is always larger than or equal to 1, but why is that?

What is the net force needed to hold the orifice plate shown in Fig. onto the pipe?

A 2.4-m-diameter tank is initially filled with water 4 m above the center of a sharp-edged 10-cm-diameter orifice. The tank water surface is open to the atmosphere, and the orifice drains to the atmosphere. Neglecting the effect of the kinetic energy correction factor, calculate (a) the initial velocity from the tank and (b) the time required to empty the tank. Does the loss coefficient of the orifice cause a signifi­cant increase in the draining time of the tank?

Define the coefficient of performance of a refrigerator in words. Can it be greater than unity?

Find $f^{\prime}(0), f^{\prime \prime}(0)$, and determine whether f has a local minimum, local maximum, or neither at x=0.$f(x)=x^{3}-x^{2}+x-1$

Intercalated discs and pacemaker cells are characteristic of (a) smooth muscle tissue. (b) cardiac muscle tissue. (c) skeletal muscle tissue. (d) a, b, and c are correct.

Determine whether the statement is true or false. A linear operator on $R^n$ is diagonalizable if and only if its standard matrix is diagonalizable.

In $2010$, renewable energy sources provided $8$ quadrillion Btu's ofthe U.S. energy consumption. The following table shows the percent provided by each renewable source.

Determine the amount of Btu's contributed by

$$\text{Wind}.$$

Show that the complex Fourier coefficients of an even function are real and those of an odd function are pure imaginary.

Why is it important for a manager to receive frequent feedback on his or her performance?

Simplify by reducing the index of the radical.

$$\sqrt[9]{x^6 y^3}$$

Identify the number as one of the following: real, imaginary, pure imaginary.

$$3+i \sqrt{5}$$

Refer to the data in the table below.

A special problem arises for the nutrient alcohol consumption. There are often a large number of nondrinkers (alcohol consumption $=0$ ) and another large group of drinkers (alcohol consumption $>0$ ). The overall distribution of alcohol consumption appears bimodal. Plot the distribution of alcohol consumption for both the diet record and the food frequency questionnaire. Do the distributions appear unimodal or bimodal? Do you think the normality assumption is appropriate for this nutrient?

What is the speed of light in a substance whose index of refraction is 1.62?